Method for producing a brake drum

Abstract

An improved method for producing a final balanced and noise suppressing brake drum including a generally closed outer end, a generally axially extending cylindrical main body, and an open inner end. The closed outer end of the brake drum includes a centrally located wheel spindle opening formed therein, and a plurality of lug bolt mounting holes spaced circumferentially around the wheel spindle opening. The cylindrical main body of the brake drum is formed during a casting operation and includes a plurality of discrete raised segments formed on an outer surface thereof. Preferably, at least three raised segments are provided on an outer surface of the brake drum, and at least two of the three segments are spaced apart from one another by generally equal angles. The discrete raised segments are provided at predetermined locations on the outer surface to reduce brake noise and are selectively machined during a machining operation to produce a final balanced brake drum.

What is claimed is: 
     
       1. A brake drum adapted for use in a drum brake assembly comprising: a hollow cylindrical brake drum defining a brake drum axis and including a generally closed outer end, a generally radially extending transition section, a generally axially extending cylindrical main body, and an opened inner end;   a plurality of discrete raised segments provided on an outer surface of said cylindrical main body, each of said raised segments having a generally stepped configuration including a generally radially extending first surface, a generally axially extending second surface, a generally radially extending third surface, a generally axially extending fourth surface, and a generally radially extending fifth surface, said raised segments extending substantially the entire axial length of said outer surface of said cylindrical main body; and   at least a portion of one of said first surface, said second surface, said third surface, said fourth surface, and said fifth surface on at least one of said raised segments being selectively machined to thereby produce the brake drum.   
     
     
       2. The brake drum defined in claim 1 wherein said brake drum is a full cast brake drum. 
     
     
       3. The brake drum defined in claim 1 wherein said raised segments are located adjacent said opened inner end. 
     
     
       4. The brake drum defined in claim 1 wherein said brake drum includes a centrally located wheel spindle opening in said opened end, and a plurality of lug bolt mounting holes spaced circumferentially around said wheel spindle opening. 
     
     
       5. The brake drum defined in claim 1 wherein said brake drum includes annular groove formed in said opened end. 
     
     
       6. The brake drum defined in claim 1 wherein at least a portion of one of said fourth surface and said fifth surface on at least one of said raised segments is selectively machined. 
     
     
       7. The brake drum defined in claim 1 wherein at least a portion of both of said fourth surface and said fifth surface on at least one of said raised segments is selectively machined. 
     
     
       8. The brake drum defined in claim 1 wherein at least two of said three discrete raised segments are spaced from each other by generally equal angles. 
     
     
       9. The brake drum defined in claim 1 wherein the brake drum is a composite brake drum. 
     
     
       10. A method for producing a brake drum adapted for use in a disc brake assembly comprising the steps of: (a) providing a brake drum defining a brake drum axis and including a generally closed outer end, a generally radially extending transition section, a generally axially extending cylindrical main body, and an opened inner end, the cylindrical main body of the brake drum including a plurality of discrete raised segments formed on an outer surface thereof, each of the raised segments having a generally stepped configuration including a generally radially extending first surface, a generally axially extending second surface, a generally radially extending third surface, a generally axially extending fourth surface, and a generally radially extending fifth surface, the raised segments extending substantially the entire axial length of the outer surface of the cylindrical main body; and   (b) selectively machining at least a portion of one of the first surface, the second surface, the third surface, the fourth surface, and the fifth surface on at least one of the raised segments to thereby produce the brake drum.   
     
     
       11. The method defined in claim 10 wherein the cylindrical body of the brake drum and the plurality of discrete raised segments are formed from the same material. 
     
     
       12. The method defined in claim 11 wherein the cylindrical body of the brake drum and the plurality of discrete raised segments are integrally formed during a casting operation. 
     
     
       13. The method defined in claim 10 wherein the plurality of discrete raised segments are generally identical to one another in size and mass. 
     
     
       14. The method defined in claim 10 wherein the plurality of discrete raised segments are located adjacent the open end of the brake drum. 
     
     
       15. The method defined in claim 10 wherein the brake drum includes three discrete raised segments. 
     
     
       16. The method defined in claim 15 wherein at least two of the three discrete raised segments are spaced apart from each other by generally equal angles. 
     
     
       17. The method defined in claim 16 wherein the equal angles is approximately 115°. 
     
     
       18. The method defined in claim 10 and further including the step of forming a centrally located wheel spindle opening in the open end of the brake drum and a plurality of lug bolt mounting holes spaced circumferentially around the wheel spindle opening. 
     
     
       19. The method defined in claim 10 and further including the step of forming an annular groove in the open end of the brake drum. 
     
     
       20. The method defined in claim 10 wherein the brake drum is a full cast brake drum. 
     
     
       21. The method defined in claim 10 wherein the cylindrical main body includes an integral raised squealer band, the squealer band including a plurality of discrete raised segments formed on an outer surface thereof. 
     
     
       22. The method defined in claim 10 wherein the brake drum is a composite brake drum. 
     
     
       23. The method defined in claim 10 wherein the brake drum is an integral hub brake drum. 
     
     
       24. The method defined in claim 23 wherein step (b) includes selectively machining at least a portion on both of the fourth surface and the fifth surface on at least one of the raised segments. 
     
     
       25. The method defined in claim 10 wherein step (b) includes selectively machining at least a portion of one of the fourth surface and the fifth surface on at least one of the raised segments. 
     
     
       26. The method defined in claim 10 wherein the brake drum is an integral hub brake drum.